1. Field of the Invention
The present invention relates to chemical production procedures and more particularly to methods of making either softeners for rubber mixtures or furnace fuel oils.
2. Description of the Prior Art
Widely used at present are methods of making either softeners for rubber mixtures or a furnace fuel oil as described in "N. I. Chernozhukov, Tekhnologia pererabotki nefti i gaza, Khimia Publishers, Moscow, 1967, pp. 133-140". The furnace fuel oil is made by mixing the residue of thermal cracking and coking processes, and the softeners are extracted with the aid of such solvents as phenol, furfural. Decreased supplies and increased costs of crude oil make it necessary to look for other sources of raw materials for making the above materials.
In particular, a production procedure was developed for making either a softener for rubber mixtures or a furnace fuel oil, comprising a thermal decomposition of vulcanized rubbers under heating in a medium of a hydrocarbonaceous solvent and a subsequent separation of the end product as described in Czechoslovak Pat. No. 106,402. It is quite obvious that used as a source material in this method is a waste rubber material. An advantage of the above production procedure consists in that, apart from the utilization of the waste material, it allows the cost of the end products to be greatly reduced.
However, this method also suffers from some substantial disadvantages. In particular, the quality of the produced softener and the furnace fuel oil is not always satisfactory, which is due to the fact that in the course of heating to the decomposition temperature a portion of the source material is locally overheated. The overheating causes coking and impairs the quality of the end product. Another disadvantage of the above production procedure consists in that the rubber mixtures (vulcanizates) produced with the aid of the obtained softener possess unsatisfactory characteristics and have high congelation temperatures.
The object of the present invention is to provide a method of making either a softener for rubber mixtures or a furnace fuel oil, wherein the conditions for the thermal decomposition and the technique of separation of the end products make it possible to preclude the coking of the source material and thus to upgrade the quality of the softener for rubber mixtures or the furnace fuel oil.